<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
    </head>
    <body>
    <script type="text/javascript">
        var a = prompt("请输入第一个数");
        var b = prompt("请输入第二个数");
        var c = prompt("请输入运算符号");
        var sum;
        if(c=="*"){
            sum= (parseInt(a))* (parseInt(b));
            alert(sum);

        }else if(c=="+"){
            sum= (parseInt(a))+ (parseInt(b));
            alert(sum);

        }else if(c=="-"){
            sum= (parseInt(a))-(parseInt(b));
            alert(sum);

        }else if(c=="%"){
            sum= (parseInt(a))% (parseInt(b));
            alert(sum);

        }
        else if(c=="/"){
            sum= (parseInt(a))/ (parseInt(b));
            alert(sum);

        }









    </script>


    </body>
</html>